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/* simple-object.c -- simple routines to read and write object files.

   Copyright 2010 Free Software Foundation, Inc.

   Written by Ian Lance Taylor, Google.

This program is free software; you can redistribute it and/or modify it

under the terms of the GNU General Public License as published by the

Free Software Foundation; either version 2, or (at your option) any

later version.

This program is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

GNU General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program; if not, write to the Free Software

Foundation, 51 Franklin Street - Fifth Floor,

Boston, MA 02110-1301, USA.  */

#include "config.h"

#include "libiberty.h"

#include "simple-object.h"

#include <errno.h>

#ifdef HAVE_STDLIB_H

#include <stdlib.h>

#endif

#ifdef HAVE_STDINT_H

#include <stdint.h>

#endif

#ifdef HAVE_STRING_H

#include <string.h>

#endif

#ifdef HAVE_INTTYPES_H

#include <inttypes.h>

#endif

#ifndef SEEK_SET

#define SEEK_SET 0

#endif

#include "simple-object-common.h"

/* The known object file formats.  */

static const struct simple_object_functions * const format_functions[] =

{

  &simple_object_elf_functions,

  &simple_object_mach_o_functions,

  &simple_object_coff_functions

};

/* Read data from a file using the simple_object error reporting

   conventions.  */

int

simple_object_internal_read (int descriptor, off_t offset,

                             unsigned char *buffer, size_t size,

                             const char **errmsg, int *err)

{

  ssize_t got;

  if (lseek (descriptor, offset, SEEK_SET) < 0)

    {

      *errmsg = "lseek";

      *err = errno;

      return 0;

    }

  got = read (descriptor, buffer, size);

  if (got < 0)

    {

      *errmsg = "read";

      *err = errno;

      return 0;

    }

  if ((size_t) got < size)

    {

      *errmsg = "file too short";

      *err = 0;

      return 0;

    }

  return 1;

}

/* Write data to a file using the simple_object error reporting

   conventions.  */

int

simple_object_internal_write (int descriptor, off_t offset,

                              const unsigned char *buffer, size_t size,

                              const char **errmsg, int *err)

{

  ssize_t wrote;

  if (lseek (descriptor, offset, SEEK_SET) < 0)

    {

      *errmsg = "lseek";

      *err = errno;

      return 0;

    }

  wrote = write (descriptor, buffer, size);

  if (wrote < 0)

    {

      *errmsg = "write";

      *err = errno;

      return 0;

    }

  if ((size_t) wrote < size)

    {

      *errmsg = "short write";

      *err = 0;

      return 0;

    }

  return 1;

}

/* Open for read.  */

simple_object_read *

simple_object_start_read (int descriptor, off_t offset,

                          const char *segment_name, const char **errmsg,

                          int *err)

{

  unsigned char header[SIMPLE_OBJECT_MATCH_HEADER_LEN];

  size_t len, i;

  if (!simple_object_internal_read (descriptor, offset, header,

                                    SIMPLE_OBJECT_MATCH_HEADER_LEN,

                                    errmsg, err))

    return NULL;

  len = sizeof (format_functions) / sizeof (format_functions[0]);

  for (i = 0; i < len; ++i)

    {

      void *data;

      data = format_functions[i]->match (header, descriptor, offset,

                                         segment_name, errmsg, err);

      if (data != NULL)

        {

          simple_object_read *ret;

          ret = XNEW (simple_object_read);

          ret->descriptor = descriptor;

          ret->offset = offset;

          ret->functions = format_functions[i];

          ret->data = data;

          return ret;

        }

    }

  *errmsg = "file not recognized";

  *err = 0;

  return NULL;

}

/* Find all sections.  */

const char *

simple_object_find_sections (simple_object_read *sobj,

                             int (*pfn) (void *, const char *, off_t, off_t),

                             void *data,

                             int *err)

{

  return sobj->functions->find_sections (sobj, pfn, data, err);

}

/* Internal data passed to find_one_section.  */

struct find_one_section_data

{

  /* The section we are looking for.  */

  const char *name;

  /* Where to store the section offset.  */

  off_t *offset;

  /* Where to store the section length.  */

  off_t *length;

  /* Set if the name is found.  */

  int found;

};

/* Internal function passed to find_sections.  */

static int

find_one_section (void *data, const char *name, off_t offset, off_t length)

{

  struct find_one_section_data *fosd = (struct find_one_section_data *) data;

  if (strcmp (name, fosd->name) != 0)

    return 1;

  *fosd->offset = offset;

  *fosd->length = length;

  fosd->found = 1;

  /* Stop iteration.  */

  return 0;

}

/* Find a section.  */

int

simple_object_find_section (simple_object_read *sobj, const char *name,

                            off_t *offset, off_t *length,

                            const char **errmsg, int *err)

{

  struct find_one_section_data fosd;

  fosd.name = name;

  fosd.offset = offset;

  fosd.length = length;

  fosd.found = 0;

  *errmsg = simple_object_find_sections (sobj, find_one_section,

                                         (void *) &fosd, err);

  if (*errmsg != NULL)

    return 0;

  if (!fosd.found)

    return 0;

  return 1;

}

/* Fetch attributes.  */

simple_object_attributes *

simple_object_fetch_attributes (simple_object_read *sobj, const char **errmsg,

                                int *err)

{

  void *data;

  simple_object_attributes *ret;

  data = sobj->functions->fetch_attributes (sobj, errmsg, err);

  if (data == NULL)

    return NULL;

  ret = XNEW (simple_object_attributes);

  ret->functions = sobj->functions;

  ret->data = data;

  return ret;

}

/* Release an simple_object_read.  */

void

simple_object_release_read (simple_object_read *sobj)

{

  sobj->functions->release_read (sobj->data);

  XDELETE (sobj);

}

/* Merge attributes.  */

const char *

simple_object_attributes_merge (simple_object_attributes *to,

                                simple_object_attributes *from,

                                int *err)

{

  if (to->functions != from->functions)

    {

      *err = 0;

      return "different object file format";

    }

  return to->functions->attributes_merge (to->data, from->data, err);

}

/* Release an attributes structure.  */

void

simple_object_release_attributes (simple_object_attributes *attrs)

{

  attrs->functions->release_attributes (attrs->data);

  XDELETE (attrs);

}

/* Start creating an object file.  */

simple_object_write *

simple_object_start_write (simple_object_attributes *attrs,

                           const char *segment_name, const char **errmsg,

                           int *err)

{

  void *data;

  simple_object_write *ret;

  data = attrs->functions->start_write (attrs->data, errmsg, err);

  if (data == NULL)

    return NULL;

  ret = XNEW (simple_object_write);

  ret->functions = attrs->functions;

  ret->segment_name = xstrdup (segment_name);

  ret->sections = NULL;

  ret->last_section = NULL;

  ret->data = data;

  return ret;

}

/* Start creating a section.  */

simple_object_write_section *

simple_object_write_create_section (simple_object_write *sobj, const char *name,

                                    unsigned int align,

                                    const char **errmsg ATTRIBUTE_UNUSED,

                                    int *err ATTRIBUTE_UNUSED)

{

  simple_object_write_section *ret;

  ret = XNEW (simple_object_write_section);

  ret->next = NULL;

  ret->name = xstrdup (name);

  ret->align = align;

  ret->buffers = NULL;

  ret->last_buffer = NULL;

  if (sobj->last_section == NULL)

    {

      sobj->sections = ret;

      sobj->last_section = ret;

    }

  else

    {

      sobj->last_section->next = ret;

      sobj->last_section = ret;

    }

  return ret;

}

/* Add data to a section.  */

const char *

simple_object_write_add_data (simple_object_write *sobj ATTRIBUTE_UNUSED,

                              simple_object_write_section *section,

                              const void *buffer,

                              size_t size, int copy,

                              int *err ATTRIBUTE_UNUSED)

{

  struct simple_object_write_section_buffer *wsb;

  wsb = XNEW (struct simple_object_write_section_buffer);

  wsb->next = NULL;

  wsb->size = size;

  if (!copy)

    {

      wsb->buffer = buffer;

      wsb->free_buffer = NULL;

    }

  else

    {

      wsb->free_buffer = (void *) XNEWVEC (char, size);

      memcpy (wsb->free_buffer, buffer, size);

      wsb->buffer = wsb->free_buffer;

    }

  if (section->last_buffer == NULL)

    {

      section->buffers = wsb;

      section->last_buffer = wsb;

    }

  else

    {

      section->last_buffer->next = wsb;

      section->last_buffer = wsb;

    }

  return NULL;

}

/* Write the complete object file.  */

const char *

simple_object_write_to_file (simple_object_write *sobj, int descriptor,

                             int *err)

{

  return sobj->functions->write_to_file (sobj, descriptor, err);

}

/* Release an simple_object_write.  */

void

simple_object_release_write (simple_object_write *sobj)

{

  simple_object_write_section *section;

  free (sobj->segment_name);

  section = sobj->sections;

  while (section != NULL)

    {

      struct simple_object_write_section_buffer *buffer;

      simple_object_write_section *next_section;

      buffer = section->buffers;

      while (buffer != NULL)

        {

          struct simple_object_write_section_buffer *next_buffer;

          if (buffer->free_buffer != NULL)

            XDELETEVEC (buffer->free_buffer);

          next_buffer = buffer->next;

          XDELETE (buffer);

          buffer = next_buffer;

        }

      next_section = section->next;

      free (section->name);

      XDELETE (section);

      section = next_section;

    }

  sobj->functions->release_write (sobj->data);

  XDELETE (sobj);

}